(ATTR_PERSIST): New constant.
	(msp430_data_attr): New function - verifies an attribute that only
	applies to variables.
	(msp430_attributes): Add noinit and persistent attributes.
	(noinit_section): New variable.
	(presis_section): New variable.
	(TARGET_ASM_INIT_SECTIONS): Define.
	(msp430_init_sections): New function - initialises the noinit and
	persist section variables.
	(msp430_select_section): Add support for noinit and persist
	attributes.
	(msp430_section_type_flags): Likewise.
	* doc/extend.texi:  Document the reent, critical, wakeup, noinit
	and persistent attributes.

tests	* gcc.target/msp430: New directory.
	* gcc.target/msp430/msp430.exp: New file.  Runs MSP430 specific
	tests.
	* gcc.target/msp430/data-attributes.c: New file.  Checks the
	noinit and persistent data attributes.

From-SVN: r228531